Research On Some Reconfigurable Problems In Distributed Embedded Systems

Because of the competition of fieldbus technologies in different industrial control fields since 1990s , various fieldbus standards exist . This situation limits the user's choice of fieldbus products ,and restricts the development of the fieldbus technologies , therefore it becomes the urgent affairs to realize the interconnection and interoperation between various fieldbusses . On the other hand , the fieldbus protocol standards , which survive in the intense competition between various fieldbus technologies , have unique consumer groups of their own and characteristic products aiming at some special requirements , it is not practical to replace all the protocols with one protocol artificially . So the research on the reconfiguration problems of networked control systems is very important . In this thesis , the reconfiguration problems of network topology , scheduling algorithm and application layer protocol in distributed embedded systems are analyzed in detail along with the references . Then the principles of the static reconfiguration algorithm and the dynamic reconfiguration algorithm of network topology are summarized , and on the basis of static topology reconfiguration , the OSPF routing protocol is improved by replacing the Dijkstra algorithm with the Genetic algorithm to find the shortest paths . Then the static scheduling algorithm and dynamic scheduling algorithm are discussed respectively, and the mixed scheduling algorithm which combines the two algorithms together is summarized , and the scheduling algorithm adopted in this thesis is put forward , and a method to reconfigure the scheduling algorithms is studied , and then a corresponding interface is put forward , then it is applied to a control switch example of a virtual laboratory system . At last , the network simulation is carried out with the OPNET software using the aforementioned algorithms along with the reconfigurable application layer interface , and the feasibility and validity of the algorithms are validated . A summary is given at the end of the thesis, and problems to be further improved or continuously researched are discussed.